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The process of meiosis 1 and 2 essay
Compare the contrast of meiosis and mitosis
The process of meiosis 1 and 2 essay
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The process of meiosis is different from many other forms of cell division. In meiosis the daughter cells only have half the number of chromosomes of the parent. What that means is that the cells produced in meiosis are not exact copies of the original cell. Meiosis is fragmented down into many stages. Every cell in the course of meiosis includes the cell growing, dividing, and spitting, and dividing again in order to create the four cells as the end product. Now I will start with the stages of meiosis. The first stage of meiosis is interphase. Just interphase alone is broken up into 3 different stages, G1 phase, S phase, and G2 phase. In G1 phase the cells grow to get ready for the cell division. In S phase the DNA gets synthesized which …show more content…
Each of the cells have precisely half the number of chromosomes from the original cell. There are many different processes go in this phase so the cell has time to prepare for the second part of meiosis. The only persistent thing is that genetic material does not copy, but in its place it continues to get divided. The next stage is prophase 2 during this phase the chromosomes start traveling to the metaphase plate again, which is at the midpoint of the cell. The next stage is metaphase 2 the chromosomes line up along the center of the cell before it breaks up into two. Then the chromatids point towards the opposite ends of the cell. The next stage is anaphase 2. This is the second to last phase in meiosis and it has many events that happen. The first event is when the sister chromatids separate and move towards the opposite ends of the pole. When this is happening the spindle fibers will lengthen and make the cell bigger. Then the paired chromatids will begin to detach from each other. Now every chromatid pair is considered to be a full chromosome. Now anaphase 2 will start getting ready for the final phase of meiosis. Both cell poles start to move even more apart and now it can be seen as splitting. By the end of this phase each pole
Each cell contains the same genetic code as the parent cell, it is able to do this because it has copied it’s own chromosomes prior to cell death. division. The. Meiosis consists of two divisions whilst mitosis is followed. in one division; both these processes involve the stages of interphase, prophase, metaphase, anaphase, and telophase.
Meiosis is specialized cellular division of sex cells. This type of cellular division occurs in single and multi-cellular organisms that undergo sexual reproduction. This process is split into two cycles: Meiosis I and Meiosis II. Prior to the start of meiosis, interphase occurs. Although interphase is not a stage of meiosis it is a vital preparatory step. It allows cellular growth, DNA replication and prepares for cellular division. Each cycle of meiosis is broken down into four stages for a total of eight stages. Meiosis I is composed of prophase I, metaphase I, anaphase I, and telophase I. Meiosis II is a repeat of each phase of meiosis I. Once meiosis is complete, the result will be four haploid daughter cells meaning that each daughter
Stem cells are undifferentiated cells that can differentiate themselves into specific cell type. There are two types of stem cells. The first one is the adult's stem cell. These stem cells can be found in various places in an adult human body, like the brain, the bone marrow or the liver. The other type of stem cells is the embryonic stem cells. These cells are found in embryos before its implantation in the mother's uterus. At this stage the embryo is divided in two types of cell. The first one is the outer cluster of cell that forms the embryo that will become part of the placenta once the embryo hatch. And the inner cluster is the source of embryonic stem cell since it consists of undifferentiated cell that will divide and differentiate to form all the organs and tissue needed in an adult organism. As stem cell are undifferentiated cell they can become whatever cell type is needed in an organism and could be the solution to diseases that are, at this date, incurable. (Medical News Today, 2013). Most of the ethic's problem of the stem cells researches come from the embryonic stem cell researches and how the cells are collected. Embryonic stem cells can be obtained in several ways. The first one is after a couple's fertility treatment, there might be some embryos left and the couple can decide to donate their embryos to research. The second option is to collect stem cells from a foetus after an abortion. And the last possibility is to use therapeutic cloning. Using an ovum from witch the nucleus was taken off and the nucleus of a somatic cell, the origin of this cell in the body doesn't matter, it can come from the skin for example, it is possible to create an embryo and get the stem cell from the created embryo. But in all of...
The process of mitosis can take place in either a haploid (23 chromosomes) or a diploid (46 chromosomes) cell. Before a cell can be ready for a mitotic division it must primarily undergo its interphase stage. Following the interphase stage several other stages come into play. These stages are prophase, prometaphase, metaphase, anaphase, and telophase. During each specific stage certain sequences of events take place that assist to the completion of the division.
There are a number of differences in meiosis; starting with the fact that meiosis only occurs in sex cells, producing a sperm and egg. We do have the same stages in meiosis which are prophase I, metaphase I, anaphase I and telophase I, but then again meiosis performs those phases twice to leave behind four cells with half the genetic material in each cell. In the first prophase I, the DNA is replicated and we again are left with chromatid pairs. Just as in mitosis, the mitotic spindles are preparing to pull the centrioles on opposite sides. There is middle to late prophase I which again is different from mitosis because at this time, the chromatids separate differently. Meaning they will not be identical genetically in the end result. Moving into metaphase I, similarly to mitosis the chromatid pairs line up in the center of the cell. The pulling begins again in anaphase I, where there is an arbitrary split-up of the pairs to either side of the cell. In telophase 1, the cell seperates and we are left with two cells containing only 23 chromosomes. Following we then start this process all over
The cell cycle is the process by which cells progress and divide. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates it’s DNA and divides, these are called proto-oncogenes. A proto-oncogene is a normal gene that could become an oncogene due to mutations. This process has mechanisms to ensure that errors are corrected, if they are not, the cells commit suicide (apoptosis). This process is tightly regulated by the genes within a cell’s nucleus. In cancer, as a result of genetic mutations, this process malfunctions, resulting in uncontrolled cell proliferation. Mutations in proto-oncogene or in a tumour suppressor gene allow a cancerous cell to grow and divide without the normal control imposed by the cell cycle. A change in the DNA sequence of the proto-oncogene gives rise to an oncogene, which
The first sub phase of this is prophase 1 and this is split up into 5 stages. The first one is leptotene and this is where the chromosomes supercoil. The second one is zygotene and this is where the homologous chromosomes form pairs and these are called bivalents. Pachytene is where crossing over occurs between the homologous chromosomes and chiasmata form. Diplotene is where they start to separate but remain attached to each other by the chiasmata. Diakinesis is the last stage and this is where they keep separating and the chiasmata moves to the ends of the chromosome (GENIE, 2010). The second phase is prometaphase and this is where the spindle fibres assemble and the chromosomes become anchored to them by their kinetochores. Metaphase 1 is where the bivalents assort randomly on the metaphase plate. This helps to create genetic diversity. Anaphase 1 is where the bivalents separate and the homologous chromosomes move to opposite poles of the cell. Telophase 1 is where the nuclear envelope reforms after disintegrating in prophase 1. Then cytokinesis is where the cell divides to create two new cells which are haploid (GENIE, 2010). The next main stage is meiosis 2 and this is where each chromosome is split into 2 sister chromatids. Prophase 2 is the first stage and this is where the chromosomes supercoil, the mitotic spindle forms and the nuclear envelope disintegrates. Metaphase 2 is where the chromosomes become attached to the
Introduction: Prevost and Dumas (1824)first proposed cell division, when they described cellular division in fertilized frog eggs. In 1858 Rudolf Virchow popularised the one-omnis cellulae cellula epigram ("Every cell originates from another existing cell like it"). Strasburger in 1873 found this epigram to be true, as he and Flemming found out that new nuclei was developed from pre existing ones. The term of mistosis was used to describe this process by Flemming in 1882(Tan 2006). Cell division is necessary for an organism to grow, mature and sustain tissue. The division of a individual cell produces a pair of daughter cells, each a fractional size of the primary cell. Prior to dividing each of the daughter cells will mature to the size of the original cell. When development is complete cell division continues as it is essential to survival. In order for cell division to be productive the genetic material and the nucleus must be twinned accurately and one copy must be distributed to each daughter cell. The copying of the cells genetic information is called DNA replication, nuclear division is called mitosis. Throughout the mitotic(M) phase the cell must undergo mitosis, a process that separates the duplicated chromosomes of a cell into two identical nuclei. It then divides to form two new respective cells during cytokinesis. Mitosis occurs solely in eukaryotic cells and the process differs in various groups (Raikov, 1994). Mitosis is split into distinct stages. Cells spend a minor part of their time involved in cell division. Somatic cells spend the bulk of their functional lives in a state known as Interphase. ...
Meiosis is a specialized form of nuclear division in which there two successive nuclear divisions (meiosis I and II) without any chromosome replication between them. Each division can be divided into 4 phases similar to those of mitosis (pro-, meta-, ana- and telophase). Meiosis occurs during the formation of gametes in animals.
The differences between the two phases of meiosis are that in meiosis I, while the cell undergoes the phases, prophase I, metaphase I, anaphase I, and telophase I, it causes the cell to divide into two with each of the cells having a double stranded chromosome. But in meiosis II, it is just the division of the the cells from meiosis I. The ending result being that four haploid daughter
Mitosis is broken down into four stages: prophase, metaphase, anaphase and telophase. When living organism needs new cells to repair damage, grow or maintain its condition, cells undergo the cell cycle.
To start this off, conception is the action of conceiving a child, and pregnancy is the period from conception to birth. They both share the same meaning: the process of getting pregnant. Conception happens when a sperm penetrates on one of the female’s eggs. Then, at around day 14 of a 28 day cycle, the egg leaves the ovary, and it is surrounded by a protective layer of cells. The fallopian tube is lined with cilia, which helps move the egg towards the womb. This is called ovulation. In the next 12-24 hours, the egg waits to be fertilized by a single sperm. The sperm then swims through the womb to meet the egg in the fallopian tube. And the sperm secretes enzymes to help penetrate the outer layer of the egg. Once the
Mitosis is a more advanced binary fission where all the organelles, DNA, RNA and chromosomes are replicated to form two identical cells. Meiosis is cell division for gametes like sperm cells or egg cells that require only half the number of chromosomes than other cells such as skin cells. In meiosis, the chromosomes first condense and sort into pairs which match and ‘relate’ (Homologous pairs). The chromosomes then ‘exchange’ data and information, this varies the outcome of the cell meaning unlike skin cells, and each cell isn’t identical. The cells then part into two groups before the cells start to split like mitosis; however, the process is then repeated in a similar manner, however, the chromatids that separate instead of the whole chromosomes, the result of mitosis is four unique cells rather than two identical
During this phase the DNA aka “deoxyribose nucleic acid” clone then forms chromatin. Chromatin is the mass of genetic material that forms into chromosomes. Interphase is divided into smaller parts: G1 Phase, S phase and G2 Phase. Throughout all the phases, the cells continuously develop by producing mitochondria, endoplasmic reticulum, and proteins. The actual division occurs during the S phase bur the G phases are mainly for the purpose of growing. Starting with the G1 phase the cell grows in preparation for certain intracellular components and DNA replication. This phase makes sure the cell is prepared for the process of DNA replication. It reviews the size and environment to ensure that is it ready to go, and cannot leave the G1 until it is complete. But what happens to a cell when it is not complete and cannot exit out of the phase? It will pause and transfer to phase G0. There’s no certain time to be in this phase but it will remain until it reaches the fitting size and is in a supportive surroundings for DNA replication. It will exit either G1 or G0 and there is no other way besides these. Then the cell will advance to the next phase which is the S phase. Synthesis, or more known as S phase is the section of the cell cycle when the DNA is wrapped into chromosomes then duplicated. This is a very important part of the cycle because it grants each of them that is created, to have the exact same genetic
All cells are the product of multiple rounds of cell growth and division, new cells are formed from existing cells, as has been the processes since the beginning of life on Earth. The reproduction of new cells is a very organized sequence of events called the cell cycle. This cycle is the essential mechanism by which all living cells reproduce whether unicellalur or mutlicelluar the basic mechanism is universal. However, variations in the details do occur from organism to organism and the cycle can start at different times in the organism’s life. The Eukaryotic cell cycle usually consist of four phases.